When gas and oil burn in vented heating systems, the dangerous fumes that are the by-products of combustion – including carbon monoxide – are released into the chimney through a connector pipe.
Funnelling these fumes out of the living area is the primary purpose of a chimney. In addition to carrying off toxic gases, chimneys also create the draft (flow of air) that provides the proper air and fuel mixture for efficient operation of the heating appliance. Unfortunately, many chimneys in daily use in homes throughout the country either are improperly sized or have conditions that make them unable to perform their intended function.
GAS – Natural gas is a clean-burning fuel, but today’s high-efficiency gas boilers pose special problems. The fumes they produce are cooler and contain high levels of water vapour, which cause more condensation than older models. Since these vapour’s also contain chlorides picked up from house-supplied combustion air, the flues are subjected to more corrosive conditions than before and can quickly deteriorate or plug up completely.
OIL – Oil flues need to be cleaned and inspected annually because deposits of soot may build up on the interior walls of the chimney. The amount of soot depends on how well tuned the boiler is and whether the house provides sufficient air for combustion. Excessive soot causes problems ranging from inefficient boiler operation to completely blocked chimneys.
To the extent that problems with either of these heating systems interfere with the flow of toxic gases and particles out of the house, they may also force carbon monoxide into the home. They may cause a one-time, high-level exposure situation or release smaller amounts more regularly over a longer period. These problems should never be ignored.
Preventing Problems
In the United Kingdom, numerous agencies and organisations now recognise the importance of annual heating system inspection and maintenance in preventing carbon monoxide poisoning. A well tuned stove or boiler, connected to a venting system or flue that is correctly sized, structurally sound, clean and free of blockages, will operate efficiently and produce a warm and comfortable home. Carbon monoxide detectors are now readily available and no home should be without at least two, one near the appliance and one near the sleeping area of the home. Detectors are NOT a substitute for routine maintenance, but can be a lifesaver should problems occur.
Considering the risks involved when gas or oil systems are neglected, and the benefits that accrue when they are properly maintained, we suggest you have your appliance serviced yearly by a qualified technician and your chimneys checked annually by a NACE registered Chimney Engineer and cleaned or repaired as necessary.
Click on the ‘Safety Info’ tab in this link for more information.
Information Updated on: 6 February 2012
